This work introduces a method for screening potential hotspots in monolithic interconnected thin-film silicon modules using injection-dependent electroluminescence (EL) imaging. The fraction of dark area of the cell in the low- and high-injection EL images, respectively, is used to extract the severity and localization information associated with a defect. For the first time, a factor, namely, severity-to-localization (SL), is introduced for each defect as the ratio of severity to localization. Further, defects are broadly classified as A, B, AB, and C modes. Mode A and Mode B are severe, where the former is a distributed defect across the cell, and the latter is a localized defect. In contrast, Mode C is a localized trivial defect. The severe defects that are neither entirely distributed within the cell area nor localized are classified as Mode AB. The SL factor values associated with A, B, AB, and C modes are ≈1, >4, between 1 and 4, and ≈1, respectively. Furthermore, the potential of four modes of defects for hotspot formation is tested following the IEC61215 standard. The hotspot endurance test results reveal that high SL factor defects, such as Mode B, always lead to hotspots, and low SL factor defects, such as Mode A and C, do not produce distinguishable hotspots. Similarly, Mode AB with a higher SL formed clear hotspots, and with a lower SL factor (<1.5) never formed hotspots. The proposed method applies to all thin-film technologies with monolithic interconnects and is, therefore, expected to gain significant attention.

Photovoltaic (PV) panel installations in buildings and transportation hubs pose additional safety challenges as the glare from the panels can impose adverse impacts like flash blindness in human eyes. This study substantiates that polymer encapsulated thin film modules offer significantly low glare levels that are essential for building integrated and transport hub installations. In this work, the glare hazard potential associated with matt ethylene tetrafluoroethylene (ETFE)-based polymer sheet used as the frontsheet for the production of flexible thin amorphous silicon (a-Si) PV modules is studied and compared with standard PV glass used in crystalline silicon (c-Si) PV panels. The specular reflectance extracted from the measured total and diffuse reflectance for an angle of incidence (AOI) of 8° and the angular intensity distribution (AID) of specular reflectance measured for AOI ranging from 10° to 80° are utilized for glare assessment of the frontsheets. The mean value of specular reflectance extracted from the measured total and diffused reflectance is as low as 0.5% for the polymer frontsheet and is 4% for glass. The AID measurements suggest that the reflection from the polymer frontsheet is highly diffusive in nature in contrast to glass and the measured specular reflectance is always close to a magnitude lower than that from glass for all AOI. With the increase in AOI, the specular AID reflectance increases exponentially for glass to become as high as 40%, which is almost 20 times less than that from the polymer frontsheet for an AOI of 80°. Further, the c-Si test structure with glass and thin a-Si PV module with matt ETFE-based polymer as frontsheet showed similar specular reflectance trends as that of glass and the polymer frontsheet, respectively.